Telephone



' "(N0 Model.)v

A. 0. WHITE.

TELEPHONE.

No. 485,311. Patented Nov. 1, 1892.

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UNITED STATES PATENT OFFICE.

ANTHONY 0. WHITE, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE AMERI- CANBELL TELEPHONE COMPANY, OF SAME PLACE.

TELEPHONE.

SIfEGIFICATION forming part of Letters Patent No. 485,31 1, datedNovember 1, 1892. Application filed March 24, 1892. Serial No. 426,271.(No model.)

To aZZ whom it may concern.-

Be it known that I, ANTHONY 0. WHITE, residing at Boston, in the countyof Sufiolk and State of Massachusetts, have invented certainImprovements in Telephones, of which the following is a specification.

The invention relates to variable-contact transmitters employingfinely-divided conducting material as a'variable-resistance mediumbetween two electrodes, and more especially to the type of instrumentknown as the granular-button transmitter.

The invention consists in details of construction whereby the tendencyto pack of the finely-divided conducting material is reduced or overcomeand undue heating of essential parts of the instrument prevented.

In the drawings, Figure 1 is a sectional elevation of a transmitter ofthe gran ular-button type embodying my invention as used forlong-distance work. Figs. 2 and 3 illustrate the construction of thebutton in detail. Fig. 4 is a rear view of the long-distance instrumentshown at Fig. 1 with the outer casing removed. Fig. 5 is a sectionalelevation representing the well-known Blake transmitter as modified toembrace my invention.

The same letters, as far as may be, represent the same parts in all thefigures; but, except when otherwise stated, the description relates moreparticularly to the transmittinginstrument shown as a whole at Fig. 1.

D is the soundreceiving disk or diaphragm.

E is a disk constituting the front or working electrode.

B is a disk constituting the heavy back electrode, and P is thefinely-divided conducting material between the electrodes.

W is a heavy metallic block, serving as a casing or frame for theelectrodes and the finely-divided conducting material, being chamberedto receive them, as shown. The finely-divided material, as in otherinstruments of the button type, is anthracite carbon, and the twoelectrodes E and B are disks of carbon; but it is not necessary that theelectrodes, both or either of them, be made of that material.Satisfactory results are obtained when granulated carbon is used betweenelectrodes of brass. The electrodes,

however, of whatever material made, should be highly polished for bestresults. As stated above, the shell or casin g W is metallic. Forsatisfactory results the metal of which it is made should havesubstantially the same coefficient of expansion as the two electrodesand the finely-divided material between them. Brass fully answers thepurpose of the invention, and so, also, would carbon; but it would notanswer the purpose to use for the shell or casing WV either wood,ebonite, or any similar material whose coelficient of expansion is verymuch larger than that of anthracite carbon and the metals ordinarilyused for the electrodes of transmitting-telephones The walls of thechamber in the block V are lined with gummed paper t' to prevent theshort-circuiting of the instrument. It will be observed that there is aconsiderable space around the periphery of the two electrodesE and B toreceive the finely-divided conducting material out of the direct path ofthe electric current. The finely-divided material in this part of thechamber not becoming so much heated in the operation of the instrumentas the portion between the "electrodes, the latter portion is permittedto expand into the former and so offer less disturbance to theelectrodes, due to its change in temperature. Moreover, thisconstruction prevents the clogging of the finelydivided material betweenthe working electrode E and the walls of the chamber XV that takes placewhen that electrode substantially fills the chamber, thereby interferingwith the proper movement of the electrode. The carbon disk or electrodeB is secured to the back on bottom of the chambered block TV by means ofa brass disk a, soldered to the electrode and secured into the block.The front electrode E is soldered to a similar disk ofbrass b, which bya threaded boss or pin 1; and nut u is secured to the inner face of amica disk m, that in turn is clamped to the sides or rim of thechambered block V by a a, secured upon the block as shown, and serves toconfine the finely-divided conducting material Within the chamber of theblock. The flexibility of the mica permits the front electrode E to havea piston-like movement in said chamber.

In the long-distance instrument shown at threaded sleeve Fig. l theblock W, or, it may 'be said, the l entire button, which has now beenfully described, is secured by a set-screw d to aheavy brassbridge-piece P, whose ends in turn are set into the metallic frame F ofthereceivingdiaphragm D, which with its dampening and insulating ring ais held in place by means of padded springs f in the ordinary manner.The frame F is set in a metallic cup-shaped outer casing O, which may bemounted in any convenient manner. M is the mouthpiece, set in the frontof the frame F.

In the long-distance instrument shown at Fig. 1 the front electrode Eand the parts immediately'connected with it, the mica disk on, the brassdisk I), and nut a are rigidly secured to the diaphragm D, as shown, bya threaded projection 19 from boss or pin p and the nut t and jam-nut t.ation of the instrument the working electrode E follows accurately thevibrations of thediaphragm.

A brief description only will suffice for the modification shown at Fig.5. It willat once be seen that the construction follows closely that ofthe Blake transmitter, the heavy chambered block N being supported onthe outer electrode-spring S of the Blake transmitter, which is adjustedto maintain a yielding pressure between the back electrode E and thediaphragm D through intervening members of the instrument. In themodification the front electrode E is not clamped or in any way fastenedto the diaphragmD. It constantly presses toward the said diaphragm,however, and is compelled to follow the movements of the said diaphragmby virtue of the spring S and the elasticity of the mica disk m. Forconvenience of construction, more especially in altering old Blakeinstruments, mechanical connection between the inner electrode E and thediaphragm is made by the interposition of a pin g, sup- Thus in the operported by a spring h.

The construction of the button in the two instruments is substantiallythe same; but in operation the two instruments difier slightly in thatwhile in the instrument shown at Fig. 1 but one of the electrodes movesand little or no advantage is gained from the elastic nature of the micadisk and any suitable flexible material might be substituted-forinstance, a thin cloth-the elastic feature in the modification shown atFig. 5, as will presently be seen, becomes important over and above theflexible feature, since the disk acts follow the movements of thediaphragm in dependently of the movements of the electrode B.

I claim- 1. The combination, with the sound-receiving diaphragm. D and asupporting-frame therefor, of the independently-supported heavychambered block IV and electrode B, secured thereto, the flexible diskon, and piston-electrode E, carried thereby, and the finely-dividedconducting material within the chamber in said block and extending aboutthe periphery of said piston-electrode E, sub stantially as described.

2. In a granular button for atransmittingtelephone, the combination,with the heavy chambered block \V, electrodes 13 and E, and[finely-divided conducting material P, of the 3 mica spring-disk m,carrying the electrode E and confining said granulated material withinthe chamber in said block WV, substantially as described.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, this 22d day of March, 1892.

ANTHONY O. \VHI'IE.

Witnesses:

GEO. WILLIS PIERCE, GEO. E. PARSONS.

vas a spring, tending to draw the electrode E from the electrode B andmake the former

